Machado-Moreira Bernardino, Richards Karl, Abram Florence, Brennan Fiona, Gaffney Michael, Burgess Catherine M
Teagasc Food Research Centre Ashtown, D15 KN3K Dublin, Ireland.
School of Natural Sciences, National University of Ireland Galway, H91 TK33 Galway, Ireland.
Foods. 2021 Sep 2;10(9):2072. doi: 10.3390/foods10092072.
Microbial disease outbreaks related to fresh produce consumption, including leafy green vegetables, have increased in recent years. Where contamination occurs, pathogen persistence may represent a risk for consumers' health. This study analysed the survival of and on lettuce plants watered with contaminated irrigation water via a single irrigation event and within stored irrigation water. Separate lettuce plants ( var. ) were irrigated with water spiked with Log 7 cfu/mL of each of the two strains and survival assessed via direct enumeration, enrichment and qPCR. In parallel, individual 20 L water microcosms were spiked with Log 7 cfu/mL of the individual strains and sampled at similar time points. Both strains were observed to survive on lettuce plants up to 28 days after inoculation. Direct quantification by culture methods showed a Log 4 decrease in the concentration of 14 days after inoculation, and a Log 3 decrease in the concentration of 10 days after inoculation. was detected in water samples up to 7 days after inoculation and was detected up to 28 days by direct enumeration. Both strains were recovered from enriched samples up to 28 days after inoculation. These results demonstrate that and strains are able to persist on lettuce after a single contamination event up until the plants reach a harvestable state. Furthermore, the persistence of and in water for up to 28 days after inoculation illustrates the potential for multiple plant contamination events from stored irrigation water, emphasising the importance of ensuring that irrigation water is of a high quality.
近年来，与食用新鲜农产品（包括叶菜类蔬菜）相关的微生物疾病暴发有所增加。在发生污染的地方，病原体的持续存在可能对消费者健康构成风险。本研究分析了通过单次灌溉事件用受污染的灌溉水浇灌生菜植株时以及在储存的灌溉水中，[具体菌株1]和[具体菌株2]的存活情况。将单独的生菜植株（[品种名称]）用添加了每株两种菌株的Log 7 cfu/mL的水进行灌溉，并通过直接计数、富集培养和定量聚合酶链反应（qPCR）评估存活率。同时，将单独的20升水微宇宙添加每株Log 7 cfu/mL的菌株，并在相似的时间点进行采样。观察到两种菌株在接种后长达28天内在生菜植株上存活。通过培养方法进行的直接定量显示，接种后14天[具体菌株1]的浓度下降了Log 4，接种后10天[具体菌株2]的浓度下降了Log 3。接种后长达7天在水样中检测到[具体菌株1]，通过直接计数在长达28天检测到[具体菌株2]。接种后长达28天在富集样品中均能回收两种菌株。这些结果表明，[具体菌株1]和[具体菌株2]菌株在单次污染事件后能够在生菜上持续存在，直至植株达到可收获状态。此外，接种后[具体菌株1]和[具体菌株2]在水中长达28天的持续存在说明了储存的灌溉水可能导致多次植株污染事件，强调了确保灌溉水质量高的重要性。
